1 /*******************************************************************************
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
3 *
4 * All rights reserved. This program and the accompanying materials
5 * are made available under the terms of the Eclipse Public License v1.0
6 * which accompanies this distribution, and is available at
7 * http://www.eclipse.org/legal/epl-v10.html
8 *
9 * Alternatively, the contents of this file may be used under the terms of
10 * either the GNU Lesser General Public License Version 2.1 or later (the
11 * "LGPL"), in which case the provisions of the LGPL are applicable instead
12 * of those above. If you wish to allow use of your version of this file only
13 * under the terms of the LGPL, and not to allow others to use your version of
14 * this file under the terms of the EPL, indicate your decision by deleting
15 * the provisions above and replace them with the notice and other provisions
16 * required by the LGPL. If you do not delete the provisions above, a recipient
17 * may use your version of this file under the terms of the EPL or the LGPL.
18 *
19 * Based on the original MiniSat specification from:
20 *
21 * An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
22 * Sixth International Conference on Theory and Applications of Satisfiability
23 * Testing, LNCS 2919, pp 502-518, 2003.
24 *
25 * See www.minisat.se for the original solver in C++.
26 *
27 *******************************************************************************/
28 package org.sat4j.minisat.constraints.cnf;
29
30 import org.sat4j.minisat.core.ILits2;
31
32 /**
33 * @author leberre To change the template for this generated type comment go to
34 * Window - Preferences - Java - Code Generation - Code and Comments
35 */
36 public class Lits2 extends Lits implements ILits2 {
37
38 private static final long serialVersionUID = 1L;
39
40 private BinaryClauses[] binclauses = null;
41
42 /**
43 *
44 */
45 public Lits2() {
46 super();
47 // TODO Auto-generated constructor stub
48 }
49
50 /**
51 * To know the number of binary clauses in which the literal occurs. Please
52 * note that this method should only be used in conjunction with the
53 * BinaryClauses data structure.
54 *
55 * @param p
56 * @return the number of binary clauses in which the literal occurs.
57 */
58 public int nBinaryClauses(int p) {
59 if (binclauses == null) {
60 return 0;
61 }
62 if (binclauses[p] == null) {
63 return 0;
64 }
65 return binclauses[p].size();
66 }
67
68 public void binaryClauses(int lit1, int lit2) {
69 register(lit1, lit2);
70 register(lit2, lit1);
71 }
72
73 private void register(int p, int q) {
74 if (binclauses == null) {
75 binclauses = new BinaryClauses[2 * capacity() + 2];
76 } else {
77 int maxid = Math.max(p, q);
78 if (binclauses.length <= maxid) {
79 ensurePool(maxid);
80 BinaryClauses[] nbinClauses = new BinaryClauses[2 * capacity() + 2];
81 System.arraycopy(binclauses, 0, nbinClauses, 0,
82 binclauses.length);
83 binclauses = nbinClauses;
84 }
85 }
86 if (binclauses[p] == null) {
87 binclauses[p] = new BinaryClauses(this, p);
88 watches[p ^ 1].insertFirstWithShifting(binclauses[p]);
89 }
90 binclauses[p].addBinaryClause(q);
91 }
92
93 }